In May, the U.S. Centers for Medicare and Medicaid Services (CMMS) released data that showed wide variation in what local hospitals charge.

According to a report by Kaiser Health News, sticker price for the 100 most common treatments and procedures for Medicare inpatients in 2011 varied dramatically among hospitals across the country, and even across towns, according to the CMS report that shines at least some light into the often-impenetrable world of American hospital pricing.

The CMMS report has sparked pointed questions from patients and policymakers about hospital charges — why they vary so drastically from place to place, how they’re set, and why they’re so much higher than a hospital’s actual costs or the payments it receives from insurers.

It is unclear if knowing hospital charges will help patients. But federal officials, proud of this first-ever national comparison, say yes. They note that patients have long found it nearly impossible to pry any useful comparative pricing information from hospitals and doctors.Others, including hospital leaders, say patients won’t benefit from knowing charges. According to the Kaiser report, even those who question the value of charge information note the report contains other numbers that could help patients compare different hospitals for particular procedures.